Dont get me wrong, The Del Bay is quite nice for sailing up/down.
One has to realize that the predominant winds for the upper and mid bay are SW (beam reaching stuff) and you usually get an onshore sea breeze near the 'points'.
Yes, its unspoiled and uninhabited for most of the bay ... and thats the 'nice' part. Only near the town of Cape May will you receive the obligatory 'severely waked' by the numerous sport fishing boats frenetically traversing the inlets, otherwise the Del. Bay is 'vacant' ... and thats a good thing if you're sailing.
If you catch the tides/current correctly you'll 'scoot', If you dont catch the tides/currents correctly you not enjoy as much. Only on a NW or SE 'blow' does it get 'especially' rough ... and these are not 'predominant' winds.